cc: Add UMA for tracking decode duration for out of raster decodes.

cc/tiles/gpu_image_decode_cache.cc

Index: cc/tiles/gpu_image_decode_cache.cc
diff --git a/cc/tiles/gpu_image_decode_cache.cc b/cc/tiles/gpu_image_decode_cache.cc
index a194751219e178254beae8ea24132f487ea9b835..d950a5f8bfa88ab9dd153ac9ba36d0d83e4832fe 100644
--- a/cc/tiles/gpu_image_decode_cache.cc
+++ b/cc/tiles/gpu_image_decode_cache.cc
@@ -173,7 +173,8 @@ class ImageDecodeTaskImpl : public TileTask {
                  "source_prepare_tiles_id", tracing_info_.prepare_tiles_id);
     devtools_instrumentation::ScopedImageDecodeTask image_decode_task(
         image_.image().get(),
-        devtools_instrumentation::ScopedImageDecodeTask::GPU);
+        devtools_instrumentation::ScopedImageDecodeTask::GPU,
+        ImageDecodeCache::ToScopedDecodeTaskType(tracing_info_.type));
     cache_->DecodeImage(image_);
   }
 
@@ -399,15 +400,19 @@ GpuImageDecodeCache::~GpuImageDecodeCache() {
 bool GpuImageDecodeCache::GetTaskForImageAndRef(const DrawImage& draw_image,
                                                 const TracingInfo& tracing_info,
                                                 scoped_refptr<TileTask>* task) {
+  DCHECK_EQ(tracing_info.type, ImageDecodeType::kInRaster);
   return GetTaskForImageAndRefInternal(
       draw_image, tracing_info, DecodeTaskType::PART_OF_UPLOAD_TASK, task);
 }
 
 bool GpuImageDecodeCache::GetOutOfRasterDecodeTaskForImageAndRef(
     const DrawImage& draw_image,
+    ImageDecodeType decode_type,
     scoped_refptr<TileTask>* task) {
+  DCHECK_NE(decode_type, ImageDecodeType::kInRaster);
   return GetTaskForImageAndRefInternal(
-      draw_image, TracingInfo(), DecodeTaskType::STAND_ALONE_DECODE_TASK, task);
+      draw_image, TracingInfo(0, TilePriority::NOW, decode_type),
+      DecodeTaskType::STAND_ALONE_DECODE_TASK, task);
 }
 
 bool GpuImageDecodeCache::GetTaskForImageAndRefInternal(